Caffeine
Caffeine doesn't taste of anything. Extracted, it's a tasteless, dull white powder that has some resale value for caffeine pills and caffeinated drinks thanks to its stimulant properties. In other words, it doesn't add anything to the taste of coffee. As everything else in this world, it is a chemical, one that can be analysed and understood - and can therefore be targeted by other chemicals or processes for removal from its carrier. The most interesting carrier of caffeine is, of course, coffee. Whilst tea is a culturally vital plant that also contains caffeine (roughly half the quantity of coffee when comparing the the drinks), coffee has a deeper culture of drinking for stimulation of the body rather than of conversation. Decaffeination , whether by carbon filter or using solvents such as methylene chloride or ethyl acetate (the latter of which exists in fruits such as apples and pears, leading some marketers to refer to a "natural" decaffeination process),